Steam-boiler



UNITED STATES PATEN T OFFICE.

SAMUEL PIERCE, OF TROY, NEIV YORK.

STEAM-B OILER.

Speccaton of Letters Patent No. 23,490, dated April 5, 1859.

To all whom it may concern:

Be it known that I, SAMUEL PIERCE, of Troy, county of Rensselaer, and State of New York, have invented a new and useful Improvement in Steam-Boilers; and I do herebyY declare that the following is a full and exact description thereof, reference being had to the accompanying drawings, making part of this specification, in which,

Figure l, is a vertical longitudinal section through the center of a locomotive boiler, with my imjnovement applied, Fig. 2, a vertical cross section at the line fr, af, of Fig. l. Fig. 55, a vertical longitudinal section through center of one of the air supplying tubes, and, Fig. '-ft. a vertical cross section at line y, y, of Fig. S.

The saine letters indicate like parts in all the figures.

It has long been known that the discharge of of atmospheric air above the lire to consume the combustible gases evolved from the fuel, conduces greatly to the economy of fuel, without this a very large portion of the combustible matter escapes from the chimney in the form of smoke and carbonio oxid: but serious difficulties have been experienced in the introduction of the jets of air. If the jets are introduced too far from the surface of the tire, the required ignition will not take place, and if applied so near, and in such manner as to induce the thorough comniingling ot' the atmospheric air and combustible gases at a sutliciently high temperature to insure thorough combustion, the apparatus employed for the discharge of the jets of air is exposed to such a high temperature to be thereby destroyed in a very short time. l? or these reasons very little use has been made of this method of cconomizing fuel and of avoiding the nuisance of smoke.

The object of my said invention, particularly in view of the growing necessity for the burning of coal, is to avoid the difficulties heretofore experienced in the combustion of the inflammable gases, and to this end my invention consists, in the employment of perforated air tubes in the fire chamber, and above the fuel, which tubes receive atmospheric air from outside the fire chamber and discharge it in numerous small jets among the gaseous products of combustion, when the said perforated air tubes are combined with water tubes surrounding them and connected with the Water legs, or other water spaces of the boiler, and also connected with the air tubes inside, by hollow stay bolts forming passages for the discharge of the numerous jets of atmospheric air among' the gaseous products of combustion and when the air and water tubes, so combined, are arranged in such manner within the lire chamber as to insure the thorough commingling of the jets of air discharged with the gaseous products of combustion, without constituting any obstacle to the feeding or managing of the lire.

In the accompanying drawings my said invention is represented as applied to that class of boilers known as locomotive boilers: but it will be obvious that it can be applied in the same manner to any other class of steam boilers. The fire chamber A, of the said boiler, is surrounded in the usual manner with water legs or spaces o, c, (Z, at the sides, front, and back communicating with the water in the body of the boiler, f, through which the smoke fines D, pass horizontally from the fire chamber to t-he smoke box E, leading to the chimney.

Within the tire chamber, and above the fire, I place a series of tubes I, extending from the front to the back water leg or space and in an inclined direction: but, instead, they may be placed across the tire chamber in an inclined position and communicating with the two side water legs, or they may be placed both longitudinally and transversely, or they may be otherwise arranged as will be presently stated. Each,

one of these tubes is double, consisting of an outer tube I, attached to the inner plates of the water legs and communicating with the water in the legs: and the inner tube I is of less diameter so as to lea-ve a sufficient space between the two for the free circulation of water: one end I2 is closed, and the other passes through the water leg and is secured to the outer plate of the boiler and communicates with the atmosphere outside; or if desired with a suitable blowing apparatus.

Both the inner and the outer tubes are connected by numerous hollow stay bolts i, which not only hold the two tubes concentric with each other, but form numerous small passages for the air, which, entering the inner tube from the outer atmosphere, or form a suitable blower, is discharged in numerous small jets among the gaseous products of combustion above the fire, and

'jured notwithstanding the close proximity to the tire. In this way I am enabled to supply the air to the combustible gases directly over the tire, where it will be sure to ignite, and thoroughly consume the combustible gases, and at the same time to protect the apparatus, employed for this purpose, from the injurious action of the required intense heat; and although I have described the said tubes as being inclined, to insure the circulation of the water by which they are protected, against the injurious action of the intense heat, I have only done so because I deem that the best mode of application; but any other mode of connection which will insure the circulation of the water through the space, between the inner and the outer tubes, may be substituted, and with this view I have contemplated placing the said double tubes in a horizontal position, and connecting the space between the inner and the outer tubes with the water in the upper part of the boiler, by branch tubes to etizect a connection of such spaces with the water in the boiler at ditl'erent levels, that the water may enter such spacesY at the lower level and, by raretaction, be made to pass through and be discharged,

with the steam generated-therein, at a higher level; other and equivalent modes of application may be substituted.

I do not claim as of my invention the application of air, in numerous small jets, by means of perforated tubes in the fire chamber of steam boilers. Nor do I wish to limit my claim to any precise position of the tubes within the tire chamber, so long as they are placed above the tire to discharge the jets of air among the gases e'volved where they are at an intense heat. Nor do I claim the use ot' hollow stay bolts for connecting tubes or other vessels. Nor do I claim the circulation of water to prevent metal from being injured by the action of intense heat. Nor do I claim a series of water tubes embodyw ing air tubes when such series are made to constitute a water table; as shown in the application of the patent granted Dec. 22nd 1857 to B. L. Griffith; but

vWhat I doclaim as my invention and desire to secure by Letters Patent, is

The employment of air tubes placed within the fire chamber of a steam boiler, substantially as described, in combination with the surrounding water tubes connected at both ends with the water spaces of the boiler and connected with the inner air tubes by means of hollow stay bolts, where the air and water tubes so combined are arranged substantially as specified for the purpose set forth. j

. SAMUEL PIERCE. TWitnesses: Y

J. N. MCINTIRE, HENRY WV. TURPIN. 

